This application claims the benefit of Japanese Patent Applications No. 2000-36936, 2000-102693, 2000-254210 and 2000-312118 which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates generally to a steering device for a car, and more particularly to a steering device for a car, which is capable of adjusting a tilt angle of a steering shaft and/or an axial position of the steering shaft.
2. Related Background Art
One of the steering devices for cars is a tilt telescopic type steering device capable of adjusting a tilt angle of a steering wheel and also adjusting an axial position of the steering wheel.
For example, in the tilt telescopic type steering device disclosed in Japanese Patent Application Laid-Open No.11-278283, an upper-sided inner column is slidably inserted into a lower-sided outer column. This upper-sided inner column is fitted with a distance bracket formed with a telescopic adjustment groove. This distance bracket is structured to come into contact with the inside of a car-body-sided bracket having a tilt adjustment groove. A fastening bolt is inserted through the telescopic adjustment groove and the tilt adjustment groove. An operation lever is fitted to one side end of this fastening bolt.
With this construction, when the operation layer is opearated, the fastening bolt moves in the axial direction, thereby releasing the fastening of the car-body-sided bracket and the distance bracket. Then, the fastening bolt moves in up-and-down direction along the tilt adjustment groove, whereby a tilt angle of the upper-sided inner column can be adjusted and an axial position thereof can be adjusted with an axial movement of the inner column along the telescopic adjustment groove.
After making the tilt and telescopic adjustments, when the operation lever is opearated in the opposite direction, the fastening bolt is moved in the axial direction and presses the car-body-sided bracket against the distance bracket. The upper-sided inner column can be thereby fastened in the state after making the tilt and telescopic adjustments. Further, both of the tilt adjustment and the telescopic adjustment can be thus made by operating one single operation lever.
In the tilt telescopic type steering device disclosed in the Publication given above, the upper-sided inner column is slidably fitted in the lower-sided outer column, thereby enhancing rigidities of the two columns.
The upper-sided inner column is not, however, necessarily directly clamped against the lower-sided outer column, and hence, if a bending load acts on the steering wheel (i.e., if the steering wheel is wrenched in the up-and-down directions), the upper-sided inner column might be moved with slight oscillations, and it can not necessarily be said that the rigidities of the two columns are high.
Note that the rigidities are, it may also be considered, increased by providing a plurality of reinforcing plates on the distance bracket provided in the upper-sided inner column, however, there might be a possibility in which manufacturing costs rise due to an increase in the number of components.
It is a primary object of the present invention to provide a steering device for a car that is capable of adjusting a tilt and/or telescopic position with enhanced rigidity of a steering column.
To accomplish the above object, according to one aspect of the present invention, a steering device for a car, comprises an inner column for rotatably supporting one end of a steering shaft, an outer column, for rotatably supporting the other end of the steering shaft, in which the inner column is slidably fitted, a couple of clamp members formed integrally with the outer column and each having an embracing surface for embracing the inner column, and a fastening member for making the couple of clamp members embrace and thus fasten the inner column by moving the couple of clamp members close to each other. The steering shaft is movable in the axial direction by releasing the fastening by the fastening member, and a telescopic position of the steering shaft thereby is adjustable.
In the steering device for the car, preferably the outer column is rotatably supported on the car body, and a tilt position of the steering shaft is adjustable when releasing the fastening by the fastening member.
According to another aspect of the present invention, a steering device for a car, comprises an inner column for rotatably supporting one end of a steering shaft, an outer column, for rotatably supporting the other end of the steering shaft, in which the inner column is slidably fitted, a couple of clamp members made by a casting process, disposed along an outer periphery of the outer column and each having an embracing surface for embracing the inner column, and a fastening member for making the couple of clamp members embrace and thus fasten the inner column by moving the couple of clamp members close to each other. The steering shaft is movable in the axial direction by releasing the fastening by the fastening member, and a telescopic position of the steering shaft thereby is adjustable.
As described above, in the steering device for the car, the inner column is directly clamped by the outer column. With this structure, even when the bending load acts on the steering wheel (i.e., when the steering wheel is wrenched in the up-and-down directions), the inner column neither moves nor oscillates slightly, and the rigidities of the two columns can be highly increased.